The invention relates generally to a film core of the type that is adapted to receive a film medium.
Radio frequency identification (RFID) tags have been used and proposed for many uses in warehousing, inventory control, process tracking, article surveillance and vehicle identification. Such RFID tags typically comprise a radio frequency transponder, an antenna, and a memory positioned on a substrate such as glass, plastic, or flexible film. A few examples of uses proposed for RFID tag technology include the following: U.S. Pat. No. 5,995,017 (Marsh et al.) discloses RFID tag use in an identification system; U.S. Pat. No. 5,859,587 (Alicot et al.) and U.S. Pat. No. 5,939,984 (Brady et al.) disclose RFID tag applications for electronic article surveillance; U.S. Pat. No. 6,232,870 (Garber et al.) discloses an application for library materials tagged with RFID devices and scanned using a handheld reader, U.S. Pat. No. 5,963,134 (Bowers et al.) discloses an inventory system that employs RFID tags attached to individual articles, especially suitable for library check-out applications; and, U.S. Pat. No. 6,127,928 (Issacman et al.) discloses a method and apparatus for using RFID tags for document tracking in office environments.
Different types of RFID devices have been developed. For low-cost applications with flexible substrate materials that are produced in high volumes, such as motion picture film or magnetic films, the following types of RFID devices are of particular interest:
(a) Capsule Types.
RFID transponders of the capsule type contain an RFID transponder encased in glass or plastic and can be easily attached to packaging components. Some examples of this type of RFID transponder are 32 mm Glass Transponders and 120 mm Cylindrical Transponders from Texas Instruments, Inc., Dallas, Tex.
(b) Flexible Substrate Types.
Provided on some type of flexible substrate, such as a polymer tape, these types of RFID transponders can be provided in ultra-thin versions, suitable for use in ID cards, luggage devices, and merchandising applications, for example. An example of this type of RFID transponder is disclosed in U.S. Pat. No. 5,574,470 (de Vall). These types of RFID transponder can be provided on reels, in a peel-and-stick configuration. Tag-It Inlays from Texas Instruments are one familiar product line providing this type of RFID transponder. The self-adhesive capability of the Tag-It inlay is particularly attractive for many of the prior art applications noted above. An RFID transponder of this type can be unobtrusively attached to a surface and hidden from view to help prevent tampering or removal. These devices have a limited bend radius, typically not less than about 0.75 in.
The cost of RFID devices varies widely, depending on factors such as whether or not these devices contain a battery, the amount of memory provided, read/write capability, antenna configurations, and packaging. The least expensive alternative is the flexible substrate type, having a price that is a small fraction of the price for capsule types.
It is recognized that there would be advantages in attaching RFID transponders to film media, such as motion picture film, to provide memory for improved tracking, management, and processing of the film medium. One way to accomplish this object without joining a transponder to the film medium itself is to associate the transponder with packaging that travels with the film.
Many types of film, including photographic, magnetic films, are provided on a film core. The film core, therefore, becomes an ideal carrier for attachment of the RFID transponder. For example, commonly assigned U.S. Pat. No. 6,247,857 (Wheeler et al.) discloses use of an RFID transponder in a system for tracking the processing of photographic film and commonly assigned U.S. Pat. No. 6,381,416 (Manico et al.) each show valuable and commercially viable approaches for using an RFID tag in conjunction with a film core. However, approaches other than those disclosed therein may also have value. In particular, there is a continuing need in the art for film core/memory systems that meet the following design considerations:
(a) Low Cost of Introduction.
Film cores are a commodity item, manufactured by the thousands. A single user of such cores may purchase hundreds or thousands of the cores. Thus the unit cost of such firm core/memory systems must be low. Moreover, existing film cores can be re-used, so that, short of being damaged in some way, the conventional plastic film core has a lifetime spanning a number of years. Thus, users of existing cores will desire a low cost method for adapting existing film cores for use in forming film core/memory systems. Glass capsule types of RFID transponder do not require an external antenna. However, these devices are several times the cost of RFID transponders on flexible substrate.
(b) Film Core Geometric Limitations.
RFID transponders provided on flexible substrate, however, are not designed for being tightly curled up in confined spaces and a minimum radius of curvature is required. Further, antenna requirements make it necessary that these devices be disposed on a flat or curved surface, without self-overlapping, to allow for the maximum available antenna length. Thus, there is a limited area on a film core on which a flexible substrate type RFID transponder can be joined.
(c) Sensitivity of the Film to Irregularities on the Core Surface.
Depending on film thickness and composition, the film substrate can be highly sensitive to irregularities in the core surface. For some types of film, irregularities in the core surface, communicated through each overlaid wrapping of the film on the core, can cause performance problems. For motion picture film, for example, an irregularity in the core can be transferred through several feet of film and can cause perceptible, periodic image aberrations that repeat in a predictable and annoying cycle.
The antenna length requirements consideration noted in (b) above prevents the use of an inexpensive RFID transponder on a flexible substrate wrapped tightly within the film core or within a small section of film core. While this type of RFID transponder could be adhered to either of the side faces of a film core, there is an increased risk of damage to the RFID transponder. Further, adhesion of a flexible substrate type RFID to this surface could interfere with the mounting of the film core in a film magazine or processing apparatus.
Because of the film sensitivity consideration noted in (c) above, simply adhering an RFID transponder on a flexible substrate directly to the outer cylindrical core surface, can, in some circumstances cause undesirable influences on film 10. In particular, the circuitry component of such an RFID transponder can create a surface irregularity that could be transmitted through a meaningful portion of motion picture film, causing an undesirable, repetitive imaging anomaly in that portion.
Thus, while in many ways, the attachment of an RFID transponder to a film core would appear to provide a uniquely valuable solution for tracking movement of a film throughout processing, there are several design considerations that must be addressed in doing so. Thus, what is needed is a film support system comprising a film core and a transponder that addresses the cost considerations, geometric considerations, and film sensitivity considerations described above.
In one aspect of the invention, what provides a film core article for carrying a length of film. The film core comprising a generally cylindrical outer surface adapted to receive said length of film, said outer surface further comprising a recess formed in the outer surface and shaped to receive a housing of a circuitry chip of a radio frequency transponder provided on a flexible substrate that is joined to the outer surface before the core receives the length of film.
In another aspect of the invention, what is provided is a film core article for carrying the length of film core. The film core article comprises a cylindrical outer surface of a film core for carrying the length of film wound thereon; said outer surface having a recess therein. A radio-frequency transponder on a flexible substrate is adhered to the cylindrical outer surface of the film core, said radio frequency transponder comprising an antenna and a radio frequency communication system having a housing fitting at least in part in said recess, so that said flexible substrate provides a generally uniform exterior surface to receive the length of film.
In still another aspect of the invention, what is provided is a film core article, comprising a radio frequency transponder fitted into a film feed slot in a cylindrical outer surface of a film core and an antenna connected to said radio frequency transponder, said antenna fabricated on a flexible substrate and wrapped circumferentially about the cylindrical outer surface of the film core.
In a further aspect of the invention, what is provided is a film core article comprising a film core having an outer wall with an exterior surface defining a generally cylindrical shape; and a transponder joined to the exterior surface, said transponder having a transceiver circuit and a memory circuit contained within a transponder housing, said housing having a housing thickness; an antenna joined to the transponder housing having an antenna thickness, and electrically cooperating with the transceiver circuit; and a substrate joined to the exterior surface of the film core, said substrate having a film engagement surface on one side of the substrate and an outer surface on the other side, with a substrate thickness defined between the sides, said substrate having the transceiver circuit and memory circuit provided wherein at least one of the outer wall, the antenna layer and the substrate has a recess defined therein to receive at least a part of the transponder housing so that the outer surface does not have a protrusion caused by the transponder housing.
In yet another aspect of the invention, what is provided is a method for forming a film core as a carrier for a radio frequency transponder. In accordance with the method a recess is formed in a cylindrical outer surface of a core said recess shaped to receive, at least in part, a housing containing transponder circuitry for a radio frequency transponder. The radio frequency transponder is affixed to the cylindrical outer surface of the core, with said housing being at least partially positioned within said recess.
In a further aspect of the invention, a method for forming a film core as a carrier for a radio frequency transponder, the method comprising the steps of inserting a transponder circuitry component of the radio frequency transponder into a film feed slot in the cylindrical outer surface of the film core and wrapping an antenna component of the radio frequency transponder circumferentially about the cylindrical outer surface of the filmcore said antenna connected to said radio frequency transponder circuitry component, said antenna fabricated on a flexible substrate.